APPLICANT'S ABSTRACT: There is yet no consensus regarding effective treatment for cocaine dependence. However, matching subtypes of patients to specific treatments and extending the benefits of short-term ambulatory treatments through the addition of maintenance treatment are promising strategies for enhancing and strengthening treatment response. This application represents a competitive continuation of R18 DA-6963 in response to NIDA Program Announcement 93-100, and will be conducted in two distinct phases: 1. In the first phase of this study, we will conduct a randomized clinical trial with 200 cocaine abusers which will prospectively test a matching hypothesis, that is, more severe cocaine abusers will have better outcome when treated with cognitive-behavioral coping skills therapy (Relapse Prevention) over a less structured, supportive approach (Interpersonal Psychotherapy). In this phase, up to 16 individual sessions will be offered over twelve weeks. 2. In the second phase of this study, we will evaluate the value of maintenance therapies as a strategy to improve the durability of the effects of brief psychotherapeutic approaches. Subjects who complete the twelve-week course of treatment and whose cocaine use has improved significantly over pretreatment levels will be randomly assigned to either (a) maintenance treatment, consisting of continuing their initial study treatment (Relapse Prevention or IPT) on a less frequent basis for six months, or (b) monthly assessment only for six months. The maintenance phase will be followed by six months of naturalistic follow- up for both groups to assess the durability of treatment effects. All treatments will be manual-guided and delivered by experienced doctoral-level therapist who will receive training and ongoing supervision to prevent drift during the course of the study. Multidimensional assessment will include ratings by a clinical evaluator blind to the subject's treatment condition. Supervised urine monitoring will be conducted twice weekly during the initial treatment phase and each assessment contact during maintenance and follow-up. All initial and maintenance treatment sessions will be videotaped for ongoing therapist supervision and process assessment. For both phases of the study, we will conduct detailed process and outcome assessments which will seek to (1) assess the discriminability and specificity of the two manual-guided treatment approaches, (2) evaluate the impact of nonspecific aspects of treatment on outcome and matching effects, and (3) detect aspects of therapy process which mediate or moderate matching effects.